NEW ORLEANS, LOUISIANA—Ask a toddler to pick up a tortilla chip lying flat on the floor, and she’ll probably break it trying. But not a 6000-kilogram elephant. The pachyderms deploy their trunks to pick up objects of all shapes and sizes, from small seeds to logs more than a meter in diameter. Mechanical engineers have now explored the limits of this dexterity and determined just how the trunk can be so strong and yet so gentle. Working with elephants at Zoo Atlanta, the engineers presented the animals with grains and variously sized cubes and granules of rutabagas, filming the feeding with two video cameras. The treats were sitting on a special scale called a force plate that measured how much force the elephant exerted. The elephant moderated how much force its 150-kilogram trunk exerted by making temporary joints in the trunk. By shifting the joint farther up the trunk, the elephant made the lower trunk lighter—and gentler—the team reports today at the annual meeting of the Society for Integrative and Comparative Biology. One elephant, Kelly, was even able to retrieve tortilla chips intact—using one-thirtieth the weight of the trunk to do so, proving these giants can grasp and suck up objects far beyond the researchers’ imaginations, they say. Such joints and more details still to be gleaned about the elephant’s grasp may one day help engineers make better rescue robots, they note.
Source: Science Mag